This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The main goal of this proposal is to evaluate whether left hemisphere planum temporale (PT) volume reduction, assessed by morphometric analysis of magnetic resonance imaging (MRI) data, is present in the parents of children with autism. Such a finding would bolster support our hypothesis that PT volume reduction represents a familial risk factor for language delay and deviance often seen in individuals with autistic disorder. Preliminary evidence from our laboratory suggests that alteration in the volume of the planum temporale in both adults and children with autism. The planum temporale (PT) is an auditory processing brain region intimately associated with language processing in the left hemisphere in normal development. Measuring the PT in non-affected family members will allow us to assess whether the PT alteration in autism is familial, the next logical step in determining if PT volume change will be a productive endophenotype. We are proposing to measure PT volume and surface area in 20 parents of children with autism, 20 age-matched adults with autism and 20 adults with no personal or familial history of autism or other developmental disorders. We hypothesize that the volume of the left PT will be significantly smaller in the parent group compared to the controls, and that the PT volume in the adult autism group will be lower than that for the parent group (consistent with the view that not all of the parents in the autism group will carry the risk factor in question). We will also measure language function and assess the family history of language development in the same three groups of adults. Measures of receptive and expressive language, as well as phonology and pragmatics, will be obtained in all of the adults and correlated to the MRI findings.